In the coating of substrates, aqueous binders, especially polyurethaneurea (PUR) dispersions, are increasingly being used. A particular feature of PUR dispersions relative to many other classes of aqueous binder is a high level of resistance to chemicals and water, high mechanical robustness, and high tensile strength and elasticity. These requirements are largely met by prior-art polyurethane-polyurea dispersions. By virtue of hydrophilic groups, the systems identified in the prior art may be self-emulsifying, meaning that they can be dispersed in water without assistance from external emulsifiers. For this purpose, ionically or nonionically hydrophilizing groups are incorporated into the polymer frameworks of the polyurethaneureas.
For the coating of wood, moreover, the coating composition is required to meet a number of further properties, such as rapid drying, great enhancement of the wood structure, effective and rapid sandability, all nevertheless with high hardness, scratch resistance and resistance to substances in everyday use that contain oils or fats, such as hand cream, for example. Consequently there is a continual demand for suitable coating compositions for wood, based on aqueous binders, to be improved in respect of these qualities.